1. Field of the Invention
The invention relates to synthetic attractant compositions useful as bait and, more particularly, to synthetic attractant compositions which are useful as bait for marine animals especially crustaceans including crabs, lobsters, as well as fish, turtles and similar marine species.
2. Description of the Related Art
To catch or harvest crustaceans, the present practice involves the use of traps. In the case of crab harvesting, traps, constructed primarily of galvanized chicken wire or similar material, of about 1 to 3 cubic feet in volume are used. Built into the center of the trap is a separate chamber, also of galvanized chicken wire, into which bait is inserted. Lobsters are caught in wooden slatted traps of about 3 to 5 cubic feet in size in which a separate bait chamber is located.
In both instances, the bait may be eels, "trash" fish such as menhaden, chicken necks, clams and similar products depending on their availability (the availability of natural products fluctuates), price and the opinion of the individual waterman on the effectiveness of the available baits. These natural baits are usually purchased in compressed frozen blocks about one cubic foot in volume and, in the case of menhaden, the blocks must be thawed prior to use; a very inconvenient step. Furthermore, menhaden bait is unpleasant and sometimes painful to handle and insert into the traps, because of the sharp fins.
The natural baits noted above all have the disadvantage of decaying rapidly. Thus, these natural baits have to be replenished as frequently as every one or two days. Commercial "crabbers" and lobster men use as many or more than 400 traps each which must be emptied and the bait replaced every one or two days.
Crabs are also caught by means of a trot line. In this method a long line, which may be up to a mile in length, is anchored at each end in the water. At about every six to eight feet along its length, a 6 to 8 foot piece of twine (string) called a "snude" line is tied so that it dangles in the water when the bait is tied to it. The waterman maneuvers his boat back and forth along the trot line which is draped over and rides on a wooden roller arm mounted on the waterman's boat. In this manner each baited string is raised from the water as the waterman works along the trot line. If a crab has attached it's claws to it to eat the bait, the waterman quickly nets the crab before the crab can slip back into the water and freedom. The use of natural bait such as eels, chicken parts, razor clams, etc. are similarly affected by availability and handling disadvantages noted above.
The deficiencies and difficulties in using natural bait as noted above has led to experimentation in using chemical attractants to lure crustaceans such as lobsters. In a paper entitled Chemical Attractants of the Florida Spiny Lobster, Panulirus Argus, Technical Paper No. 10, October 1978, Barry W. Ache, Bruce R. Johnson and Edward Clark, all of Florida Atlantic University, it was reported that the chemical stimuli controlling feeding include simple organic compounds such as amino acids and their derivatives. They also recognized that such compounds, once evaluated for effectiveness and appropriately packaged, could provide an effective, economical and convenient artificial bait for marine organisms. The paper describes the results of experiments with synthetic attractants.
Many compounds having some attractant properties for lobsters are listed in that paper. These compounds were evaluated as standard sea water solutions aliquoted into tanks containing lobsters. Obviously, this technique is not practical for commercial application in a natural environment (open water) because the attractant solutions will rapidly diffuse away from the "catching" site since there is nothing to prevent rapid diffusion.
Controlled release attractants are required for practical application of synthetic attractants as bait in a natural environment where crustaceans are found. Releasants reported in the literature include gelatin, polyacrylamide, agar gel, as well as attractants laminated between two barrier layers such as polyvinyl chloride or unbleached muslin. However, these releasants exhibit serious deficiencies. Gelatins dissolve rapidly in sea water, polyacrylamide exhibits gelling difficulties when combined with attractant solutions and the agar gels have weak mechanical properties which preclude the rough handling present in commercial operations.
Difficulties also arise in using barrier layer laminations of attractants. Where the attractant is water soluble, diffusion through a protective barrier layer such as polyvinyl chloride can not readily take place and, if muslin is used in the construction as noted above, the attractant would simply rapidly dissolve away and disappear through the textile fabric. If the attractant is organic soluble, the polymer barrier layer may become plasticized and lose its mechanical integrity as well as its ability to control the diffusion of the attractant.
Accordingly, it may be appreciated that the prior art synthetic attractants and releasants are deficient in meeting optimum or even acceptable levels of performance as bait in a natural environment. The present invention has overcome the deficiencies noted above and provides a synthetic attractant composition exhibiting excellent properties for use as bait for crustaceans.